The present inventions relate generally to storage devices that support pallets and their loads. More particularly, the present inventions relate to storage devices that facilitate the picking of individual cases or items from pallets that are stored on the floor under a rack type storage structure. The devices of the present inventions enable two-deep storage of pallets on the floor and the automatic presentation of the rear pallet to the access aisle for easy picking of items stored on the pallet using a cart that cantilevers from the end of the rails.
There are numerous types of storage systems available to store a variety of loads. For example, in the grocery industry, shelf type storage racks in conjunction with pushback racks are widely used. In general, these systems are configured to form shelves that may directly support pallets and their loads or which may include pushback or other storage systems. In a typical grocery warehouse, the storage racks are arranged to form aisles for access by order pickers and machinery such as straddle trucks and lift trucks. The order pickers pick individual items from the pallets on the lower level and the floor, and the machinery is used to store, retrieve and/or transfer the full pallets from the upper levels.
Again by reference to a typical rack structure in the grocery sector, the first shelf of the storage rack is typically 48″ from the floor and each of the shelves above the first shelf are spaced approximately every 48″ or at other increments as required for the facility. In addition, such shelves are typically sized to be able to support and store two pallets wide and two pallets deep between each of the rack trusses and the transverse and lateral beams. Generally, such shelves are 96″ deep by 96″ wide. These racks may extend from floor to ceiling and store thousands of pallets.
Because of the height of the typical shelves, storage and removal of pallets and their loads on the second and higher shelves are done with straddle and/or fork lift trucks, since the second shelf is typically 8′ off of the floor. That leaves the floor and the first shelf (4′ off the floor) from which individual items may be picked from the pallets by the order pickers. The first shelf is typically provided with a well known two-deep pushback system that presents the rear pallet to the front for easier picking. However, a pushback rack level is not practical for use on the floor because, among other things, it interferes with the straddles of a straddle truck which is used to place and remove the pallets at these locations. Thus, in order to reach items on the rear pallet on the floor, an order picker has to crawl under the first shelf to reach the rear pallet. Clearly, it is difficult and dangerous for an order picker to reach items on the rear pallet on the floor. This potentially dangerous situation may be avoided by eliminating storage of the rear pallets on the floor. Alternatively, a fork lift truck may be used to move the rear pallet to the front as needed. Not using the rear position is a waste of space and reduces storage density. And, using a truck to rearrange the pallets is an inefficient use of resources and takes additional time.
Accordingly, there is a need to make the items on a rear pallet of a two-deep set-up readily accessible, while at the same time maintaining maximum storage density. There is also a need to achieve such accessibility at a minimum of expense and without the need for special lift equipment and the like. In addition, there is a need for the convenient presentation of a pallet and its load in single-deep storage settings.